Sen. Heidi Heitkamp wanted to avoid turning the crude oil export ban into the next monster of a Keystone XL Pipeline debate.

"It took on so much more symbolism," Heitkamp said of the pipeline that became the subject of intense campaigning on both sides. "When we started with this issue, my main goal was to not get 'Keystoned.' To not make this so polarizing that people ... got so hardened on either side that there wasn't an opportunity for negotiation."

The North Dakota Democrat recalled in a Roll Call interview that by the time she arrived in the Senate in 2013, the pipeline project had already taken on a life of its own as a partisan flash point despite Democratic support from more moderate Democrats from production states.

"I think we had already gotten this polarized view of Keystone," Heitkamp said. "Views were already really irrationally polarized on Keystone, and I used to say it all the time. I don't know why people overreact to this."

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So when Heitkamp set out to be a Democratic voice in support of rolling back the decades-old prohibition on exporting crude, she knew that a different approach would be needed to get a bill to President Barack Obama's desk that he or his autopen would sign into law.

Heitkamp's office said she began discussing the proposal with Democratic senators back in the fall of 2014, also guest-hosting CNBC's morning program "Squawk Box" to discuss oil exports with Hess Corporation CEO John Hess. Over the ensuing year, Heitkamp became something of a fixture on business television and at panel discussions and other events pushing the overturn of the oil export ban, despite its unpopularity among many Democrats.

"Even if you could get it through Congress, which I doubted, you were going to get a veto, and you weren't going to get it without a package," Heitkamp said. "That's why I knew that an effort to put it on as a standalone on transportation wouldn't be successful."

Heitkamp was referring to an ill-fated effort to lift the export ban during negotiations over the long-term highway legislation that Obama recently signed into law. Heitkamp's home state colleague, Republican Sen. John Hoeven, said that bid was significant in building momentum for the ban to ultimately make it into the omnibus.

"I really tried to create pressure to do it on the transportation bill, hoping we'd get it there," Hoeven said of the unsuccessful effort, adding that he thought it set up opponents of the ban to ultimately prevail in the omnibus talks.

Hoeven said Wednesday that he focused on making the substantive case in getting the policy changed through legislation.

"All along I argued on the merits. I mean, this is about growing our economy. This is about more jobs. This is about national security through energy security working with our allies," Hoeven said. "I always worked it on the merits. I get that there are a lot of other considerations. I know that, but I pushed it on both sides of the aisle on the merits."

Energy and Natural Resources Chairwoman Lisa Murkowski, R-Alaska, was another key player in pushing the legislation.

"Allowing oil exports is an important step forward in ensuring that our energy policies reflect our nation’s renewed abundance of resources. Not only will oil exports help safeguard our long-term economic prosperity, but it will also spur job creation across the country and deliver much-needed revenue to state and local governments," Murkowski said in a statement.

"Certainly I think the work that we did, or that I did, within the caucus to try and build at least some understanding and awareness of this issue, led to the willingness of the caucus to basically give the green light to a negotiation on oil exports," Heitkamp said.

Heitkamp contends that in the end, there would not have been a big package without the oil export language, which was touted as a key victory in the omnibus talks by Republicans on both sides of the Capitol.

"I honestly don't believe there was a point where this could have fallen apart, but you know I've done big negotiations," Heitkamp said. "I've seen when stakes are high how things can fall apart, and sometimes it's the smallest of things that can cause rancor and lead to people walking away."

She said that in particular she did not expect that a tenuous agreement would fall apart even when Senate Minority Leader Harry Reid, D-Nev., came to the floor Tuesday morning to highlight requirements for a deal regarding wind and solar energy. That ultimately was key to the trade, with Democrats getting tax provisions they favored for renewable sources, with angst among environmentally focused Democrats.

Massachusetts Democratic Sen. Edward J. Markey went so far as to call the swap a "Trojan horse."

"Lifting the crude oil export ban is nothing more than Big Oil corporate welfare," Markey said in a statement. The oil industry wants to send our oil overseas to the highest bidder even as we still import millions of barrels of oil every day from nations around the world in unstable regions. This repeal isn’t about helping consumers at the pump, it's about pumping up Big Oil’s profits."